Effects of a 60 Hz Magnetic Field Exposure Up to 3000 μT on Human Brain Activation as Measured by Functional Magnetic Resonance Imaging

• Published in: PloS one Vol. 10; no. 7; p. e0132024
• Main Authors: Legros, Alexandre, Modolo, Julien, Brown, Samantha, Roberston, John, Thomas, Alex W
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.07.2015; Public Library of Science (PLoS)
• Subjects: Activation; Adult; Biochemistry, Molecular Biology; Bioengineering; Biophysics; Brain; Brain - physiology; Brain Mapping; Brain research; Change detection; Cognition; Cognitive ability; Cognitive science; Cognitive tasks; Cortex; Excitability; Exposure; Feasibility studies; Female; Functional magnetic resonance imaging; Humans; Imaging; Life Sciences; Low frequency; Magnetic Fields; Magnetic resonance; Magnetic Resonance Imaging; Male; Medical imaging; Medical research; Memory; Mental task performance; Motor Activity; Motor task performance; Nervous system; Neural networks; Neural plasticity; Neuroimaging; Neuroscience; NMR; Nuclear magnetic resonance; Physiology; Psychomotor Performance; Residual effects; Resonance; Studies; Synaptic plasticity; Time Factors; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0132024

Several aspects of the human nervous system and associated motor and cognitive processes have been reported to be modulated by extremely low-frequency (ELF, < 300 Hz) time-varying Magnetic Fields (MF). Due do their worldwide prevalence; power-line frequencies (60 Hz in North America) are of particular interest. Despite intense research efforts over the last few decades, the potential effects of 60 Hz MF still need to be elucidated, and the underlying mechanisms to be understood. In this study, we have used functional Magnetic Resonance Imaging (fMRI) to characterize potential changes in functional brain activation following human exposure to a 60 Hz MF through motor and cognitive tasks. First, pilot results acquired in a first set of subjects (N=9) were used to demonstrate the technical feasibility of using fMRI to detect subtle changes in functional brain activation with 60 Hz MF exposure at 1800 μT. Second, a full study involving a larger cohort of subjects tested brain activation during 1) a finger tapping task (N=20), and 2) a mental rotation task (N=21); before and after a one-hour, 60 Hz, 3000 μT MF exposure. The results indicate significant changes in task-induced functional brain activation as a consequence of MF exposure. However, no impact on task performance was found. These results illustrate the potential of using fMRI to identify MF-induced changes in functional brain activation, suggesting that a one-hour 60 Hz, 3000 μT MF exposure can modulate activity in specific brain regions after the end of the exposure period (i.e., residual effects). We discuss the possibility that MF exposure at 60 Hz, 3000 μT may be capable of modulating cortical excitability via a modulation of synaptic plasticity processes.